Pushbutton alternate action switch with a contact on the cam surface of the alternate action mechanism

ABSTRACT

A pushbutton switch having a guide track with contact means coacting therewith arranged so that electrical circuit changeover is effected only on the release stroke of a reciprocative slider bar.

United States Patent [72) Inventor Eric George Hansen Milwaukee, Wis.[21] Appl. No. 37,948 [22] Filed May 18, 1970 [45] Patented Nov. 30,1971 [73] Assignee Globe-union Inc.

Milwaukee, Wis.

[54] PUSHBUTTON ALTERNATE ACTION SWITCH WITH A CONTACT ON THE CAMSURFACE OF THE ALTERNATE ACTION MECHANISM 5 Claims, 5 Drawing Figs.

[52] U.S.C1 200/153J [51] lnt.Cl .rH0lh 13/56 [50] Field 01 Search200/153 .1,

Primary ExaminerDavid Smith Jr.

Assistant Examiner-Robert A. Vanderhye Atl0rneysJohn Phillip Ryan, GlennA. Buse, Donald D.

Benton and David T. Terry ABSTRACT: A pushbutton switch having a guidetrack with contact means coacting therewith arranged so that electricalcircuit changeover is effected only on the release stroke of areciprocative slider bar.

PUSHBUTTON ALTERNATE ACTION SWITCH WITH A CONTACT ON THE CAM SURFACE OFTHE ALTERNATE ACTION MECHANISM BACKGROUND OF THE INVENTION Field of theInvention This invention relates to electrical switches, and moreparticularly, to electrical pushbutton switches.

Electrical pushbutton switches are typically constructed so that anelectrical circuit changeover is effected upon both a depression andrelease of a reciprocative bar, e.g., an electrical circuit is completedupon depression of the slider bar and is opened when the slider bar isreleased to the deactuated position. For some applications, it isdesirable to have a pushbutton switch capable of making an electricalsystem changeover only on a release stroke of the slider bar. Forexample, such a switch finds applications in some impact detonativedevices where the pushbutton is depressed and the device becomesactivated upon release of the slider bar when an electrical circuitchangeover is made. Upon impact the slider bar is depressed again and,upon a second release of the slider bar, the explosive is detonated whenanother electrical circuit changeover is made. The pushbutton havingthis type action also can be used as a motion switch which triggers anappropriate electrical circuit when a depressing load is removed fromthe slider bar.

SUMMARY OF THE INVENTION The primary object of this invention is toprovide a simple, inexpensive pushbutton switch capable of making anelectrical circuit changeover only on release strokes.

The pushbutton switch assembly of this invention includes a housing; aguide track located inside the housing; separate strips of electricallyconductive material secured to isolated sections of the bottom of theguide track, each being connected to separate external terminals; aresilient plate member also connected to a separate external terminal;and a reciprocative slider bar carrying a contact member, one end of thecontact member slidably engaging the resilient plate member and theother end thereof being urged into slidable contact with the bottom ofthe guide track by the plate member. The guide track and conductivestrips are arranged so that, as the slider bar is released, the end ofthe contact member in slidable contact with the bottom of the guidetrack moves from one conductive strip to another, while the other endalways remains in contact with the resilient plate member, therebyeffecting a circuit changeover.

BRIEF DESCRIPTION OF THE DRAWING FIG. 1 is a perspective view of apushbutton switch exemplifying this invention.

FIG. 2 is a plan view, partially in section, of the switch illustratedin FIG. 1 with the top portion of the housing removed.

FIG. 3 is a cross-sectional view, partially broken away, taken along theplane designated by 3-3 in FIG. 2 with the top portion of the housinginstalled.

FIG. 4 is a plan view, partially broken away, showing the guide trackcontour and the various positions of the contact member during movementof the slider bar.

FIG. 5 is an elevation view taken along the plane designated as A-A inFIG. 2 showing the profile of the bottom of the guide track and thepositions of the contact member relative to the levels and stops thereofduring movement of the slider bar.

DESCRIPTION OF THE PREFERRED EMBODIMENTS Referring to the drawing,pushbutton switch exemplifying this invention includes a two-piecehousing 12, constructed from an insulating material and having a topportion 14 and a bottom portion 16, a slider bar 18 slidably mounted inand extending outwardly from housing 12, return spring 20,

pushbutton 22 and external terminals 24. 26 and 28 for connecting theswitch to the appropriate electrical circuits.

Disposed inside of the bottom portion 16 of housing 12 is a closedcontour guide track 30 incorporating a hollow cam notch with two pointsor peaks 32 and 34 and a variable depth forming bevels and stops 36, 38,40 and 41. The guide track 30 can be molded integrally into the bottomportion of housing I2 or can be a separate component which is attachedto the inside of the bottom portion of housing 12 in any convenientmanner, such as by bonding with an adhesive.

A resilient, plate or blade member 42, constructed from an electricallyconductive material, such as silver-plated brass, is disposed inside thetop portion 14 of housing I2 and is connected electrically to terminal24. Plate member 42 and terminal 24 can be formed as a single unit orcan be separate components connected electrically in any suitablemanner, such as by soldering.

Slider bar 18, made from an insulating material, includes an aperture 44extending laterally therethrough in which free floating contact member46, made from an electrically conductive material, is carried. As shownin FIG. 3, contact member 46 can be a cylindrical-shaped pin withhemispherical upper and lower ends 48 and 50, respectively, or can be ofany other convenient shape capable of performing the function describedhereinafter. Aperture 44 is somewhat larger than the outside diameter ofcontact member 46 so that it is free to move with a rocking movementwhen slider bar 18 is actuated. Plate member 42, acting as a leaf springslidably engages the upper end 48 of contact member 46 and urges thelower end 50 of contact member 46 into slidable engagement with thebottom of guide track 30 as contact member 46 is guided along thecontour thereof during the actuation of slider bar 18.

As shown in FIGS. 2 and 5, strips 52 and 54 of the electricallyconductive material are secured to the bottom of the guide track 30 withinsulating sections 56 and 58 separating them. Conductive strips 52 and54 are connected electrically to terminals 26 and 28, respectively.

As shown in FIG. 5, the bottom of guide track 30 is preferably formedwith recesses to accommodate conductive strips 52 and 54 and insulatingsections 56 and 58 are an integral pan of the base in which guide track30 is located. The recesses are preferably the same depth as thethickness of conductive strips 52 and 54 so that there is a smoothmovement of contact member 46 as it moves along the contour of guidetrack 30 as described hereinafter.

Conductive strips 52 and 54 can be formed from a thin sheet of metalsuch as silver-plated brass, and adhesively bonded to the bottom of theguide track 30 with a suitable adhesive. Conductive strip 52 andterminal 26, as well as conductive strip 54 and terminal 28, can beformed as single units or can be separate components connectedelectrically in any suitable manner. Alternatively, conductive strips 52and 54 can be formed from a thin metallic foil, such as a silver-copperalloy foil, which is adhesively secured to the bottom of guide track 30or by depositing a conductive path by conventional electroplatingtechniques. When the latter such techniques are used, terminals 26 and28 are separate components and are connected electrically to theirrespective conductive strips.

Referring to FIGS. 2, 4 and 5, the operation of the pushbutton switchwill be described. In FIG. 4 the conductive strips 52 and 54 have beenremoved for the sake of clarity in showing the contour of the bottom ofguide track 30. When slider bar 18 is in the deactuated position, thelower end of contact member 46 is in position 60 in guide track 30 witha conductive path existing between terminals 24 and 28 via plate member42, contact member 46 and conductive strip 54. As slider bar 18 isdepressed, the lower end of contact member 46 is guided along thecontour of guide track 30 in the direction of arrow 62 and rides overbevel 38 into position 64 when slider bar 18 becomes fully depressed.During this inward stroke of slider bar 18, the upper end of contactmember 46 rides in contact with plate member 42 and the lower end ofcontact member 46 rides in contact with conductive strip 54 therebymaintaining the conductive path between terminals 24 and 28. Upon therelease of slider bar [8, bevel 38 prevents contact member 46 from beingreturned backwards under the influence of return spring 20 and thereforemoves in the direction of arrow 62 and rides over bevel 40 towardsposition 66, contact member 46 being able to rock or slant freelybecause of the side play permitted by the size and shape of aperture 44.During this release stroke, the upper end of contact member 46 continuesto ride in contact with plate member 42 but the lower end thereof passesover insulating section 58 and contacts conductive strip 52. Hence, theconductive path between terminals 24 and 28 is broken and a conductivepath is established between terminals 24 and 26 via plate member 42,contact member 46 and conductive strip 52. Bevel 40 prevents contactmember 46 from being returned backwards under the influence of returnspring 20 thereby maintaining contact with conductive strip 52.

When slider bar 18 is depressed again, the lower end of contact member46 is prevented from returning backwards by bevel 40 and therefore movesin the direction of rotation of arrow 62 and rides over bevel 41 towardsposition 68. During the second depression of slider bar 18, the upperand lower ends of contact member 46 remain in contact with plate member42 and conductive strip 52, respectively, thereby maintaining aconductive path between terminals 24 and 26. Upon release of slider bar18, bevel 41 prevents contact member 46 from being returned backwardsunder the influence of return spring 20 and contact member 46 returns tohome position 60. The bottom of guide track 30 is sloped along theentire right leg and ends in bevel 36 which prevents contact member 46from returning backwards when slider bar 18 is depressed again. Duringthe second release stroke, the upper end of contact member 46 continuesto ride in contact with plate member 42 with the lower end thereofpasses over insulating section 56 and contacts conductive strip 54.Hence, the conductive path between terminals 24 and 26 is broken and theconductive path between terminals 24 and 28 is reestablished.

As shown in FIG. 3, the upper portion of housing 12 is preferablyconstructed with a nib 70 into which plate member 42 and terminal 24 andpress-fitted before assembly of the housing. Upon assembly of housing12, nib 70 is press-fitted into aperture 72 in the lower portion 16 ofhousing 12. As seen in FIG. 2, the lower portion 16 of housing 12 isalso provided with a plurality of nibs 74 which are press-fitted intoapertures (not shown) of the upper portion 14 of housing 12 uponassembly. .This structure provides simple and inexpensive means forassembling the housing. The plate member and upper portion of thehousing can be assembled as a subassembly in proper alignment, as can bethe lower portion of the housing, the conductive strips, the slider bar,the contact member, the return spring, and the pushbutton. The finalassembly is completed by merely fitting the two-piece housing together.

lt should be understood that various alterations and modifcations may bemade in the structure of the preferred embodiment of this inventiondescribed without departing from the scope and spirit thereof.

1. A pushbutton switch comprising:

a. a housing b. a guide track of the heart cam type with the bottomthereof having bevels and stops disposed inside said housmg:

c. electrically conductive material disposed on selected first andsecond sections of the bottom of said guide track, said first and secondsections of conductive material being electrically insulated from eachother and connected to first and second terminal means, respectively,for external electrical connection;

d. a resilient member of electrically conductive material disposedinside said housing and connected to a third terminal means for externalelectrical connection; e. a reciprocative slider bar slidably mounted inand extend ing out of said housing carrying an electrically conductivecontact means, one portion of said contact means slidably engaging saidresilient member which urges another portion of said contact means intoslidable engagement with the bottom of said guide track; and

f. said contact means coacting with said resilient member and said guidetrack so that a changeover between a first electrical path from saidfirst to said third terminal means and a second electrical path fromsaid second to said third terminal means is effected only upon a releasestroke of said slider bar.

2. The pushbutton switch according to claim I wherein the bevels andstops of said guide track and said first and second sections ofconductive material are arranged so that, upon an initial depression ofsaid slider bar, a said first electrical path is maintained, uponrelease of said slider bar after an initial depression said firstelectrical path is opened and said second electrical path is completed,upon a second depression of said slider bar said second electrical pathis maintained and upon release of said slider bar after the seconddepression said second electrical path is open and said first electricalpath is completed.

3. The switch according to claim 2 wherein said slider bar includes anaperture and said contact member is a cylindrical pin loosely disposedthrough said aperture.

4. The pushbutton switch according to claim 3 wherein said first andsecond sections of conductive material comprise a thin metallic layeradhesively bonded to the bottom of said guide track.

5. The pushbutton switch according to claim 3 wherein said first andsecond sections of conductive material comprise a thin metallic layerelectrically deposited to the bottom of said guide track.

1. A pushbutton switch comprising: a. a housing b. a guide track of theheart cam type with the bottom thereof having bevels and stops disposedinside said housing: c. electrically conductive material disposed onselected first and second sections of the bottom of said guide track,said first and second sections of conductive material being electricallyinsulated from each other and connected to first and second terminalmeans, respectively, for external electrical connection; d. a resilientmember of electrically conductive material disposed inside said housingand connected to a third terminal means for external electricalconnection; e. a reciprocative slider bar slidably mounted in andextending out of said housing carrying an electrically conductivecontact means, one portion of said contact means slidably engaging saidresilient member which urges another portion of said contact means intoslidable engagement with the bottom of said guide track; and f. saidcontact means coacting with said resilient member and said guide trackso that a changeover between a first electrical path from said first tosaid third terminal means and a second electrical path from said secondto said third terminal means is effected only upon a release stroke ofsaid slider bar.
 2. The pushbutton switch according to claim 1 whereinthe bevels and stops of said guide track and said first and secondsections of conductive material are arranged so that, upon an initialdepression of said slider bar, a said first electrical path ismaintained, upon release of said slider bar after an initial depressionsaid first electrical path is opened and said second electrical path iscompleted, upon a second depression of said slider bar said secondelectrical path is maintained and upon release of said slider bar afterthe second depression said second electrical path is open and said firstelectrical path is completed.
 3. The switch according to claim 2 whereinsaid slider bar includes an aperture and said contact member is acylindrical pin loosely disposed through said aperture.
 4. Thepushbutton switch according to claim 3 wherein said first and secondsections of conductive material comprise a thin metallic layeradhesively bonded to the bottom of said guide track.
 5. The pushbuttonswitch according to claim 3 wherein said first and second sections ofconductive material comprise a thin metallic layer electricallydeposited to the bottom of said guide track.